They aren’t in mempool, so don’t look at that. Mempool is only for very recent transactions that are not yet in a block.
Are you saying the balance is zero?
You say you see all the past transactions… If you see the past transactions and the balance is zero, you should also see the transactions where the coins were moved out of your wallet to someone else.
I could help explain if you send me a screenshot of your wallet or even just send me the address so that I can look at an explorer to explain what we can see about the history of those wallets.
You’re welcome to p.m. with me if you don’t want to post the address publicly.